Field
Embodiments described herein generally relate separation of ores into a purified ore and gangue. More particularly, such embodiments relate to depressant/dispersant compositions and methods for using same to aid in the separation of the ores.
Description of the Related Art
Flotation, e.g., froth flotation and reverse froth flotation, coagulation, flocculation, filtration, and sedimentation, are widely used separation processes for the beneficiation of ores and other solids present as a component in a liquid suspension, dispersion, solution, slurry, or other mixture. The separation is accomplished based on differences in the tendency of various materials to associate with rising gas (usually air) bubbles. Various additives are commonly incorporated into the flotation liquid to improve the selectivity of the separation process. For example, substances identified as “collectors” can be used to chemically and/or physically absorb preferentially onto one of the substances in the liquid mixture to render it more hydrophobic and more amenable to flotation. Conversely, “depressants” are often used in conjunction with collectors, to render other materials in the mixture, e.g., gangue, less likely to associate with the air bubbles, and therefore less likely to be carried into the froth concentrate and more likely to remain in the underflow or tailings.
Various dispersants, depressants, or dewatering agents for improving flotation separations are known in the art and include guar gum, sodium silicate, starch, tannins, dextrins, lignosulphonic acids, carboxymethyl cellulose, cyanide salts and others. Because different substances in suspension, dispersion, or slurry are affected differently by the “collector” and/or the “depressant,” a degree of separation is obtained by this process. Despite the large offering of dispersants, depressants, or dewatering agents known in the art, an adequate degree of refinement in many cases remains difficult to achieve, even, in the case of froth flotation, when one or more flotations are employed.
There is a need, therefore, for improved compositions for use in separation processes such as froth flotation and the separation of solid contaminants from liquid mixtures.